1. Field of the Invention
This invention generally relates to a dishwasher having a liquid spraying system for spraying liquid onto utensils to accomplish cleaning.
2. Description of the Related Art
The majority of conventional dishwashers for cleaning utensils, such as silverware, dishes, plates, bowls, glassware, pots, and pans, utilize a liquid sprayer for spraying liquid onto the utensils to remove soils. The sprayer is coupled to a pump or similar means to supply pressurized liquid to the sprayer to produce spray for cleaning the utensils. A wash liquid can be water or water mixed with a detergent, a drying aid, a spot reducer, or any other similar product that facilitates excellent cleaning of the utensils.
The spraying apparatus is commonly a rotating spray arm having multiple nozzles and is driven by the torque produced by two outwardly-directed nozzles on the ends of the spray arm. The nozzles direct a focused stream of wash liquid known as a jet at the utensils to clean and rinse the utensils. As the spray arm rotates, the jets rotate with the arm. This type of spray system relies on moving focused streams of high pressure liquid for cleaning.
A disadvantage of this type of sprayer is that a lot of the cleaning performance relies on the jet impacting the utensil to remove the soils by force. Depending on how the utensils are arranged, it is not always possible for every portion of a utensil to be contacted by the jet. To maintain stable hydraulic operation of the jets, a substantial amount of water is used, which may lead to an undesirable low wash aid concentration during cleaning, which can reduce the cleaning ability of the dishwasher. This leads to another disadvantage in that wash aids, such as detergents, are not always evenly distributed on the dishes as the jets do not directly contact all portions of the utensils. The deflecting and splattering of the liquid off of the utensils can further distribute the wash aid, but this method is hit and miss and highly dependent on the relative positioning of the utensils. Thus, it cannot be relied upon. The jets also produce significant acoustic sound levels due to the forcefulness with which the liquid jets are propelled onto various surfaces in the dishwasher.